The US Department of Defense has awarded two grants worth $200,000 to Perpetua Resources to study the potential for military-grade antimony production from its Stibnite Gold Project in Idaho.
If successful, this could be a new entry for domestic antimony production after US Antimony plant in Thompson Falls, Montana, which processes concentrate from Mexico. But it would be the first entirely US-sourced antimony, though not the first such production from the site. The aptly named Stibnite site produced more than 90% of the antimony used by the U.S. during WWII and was influential in establishing the military specitication (Mil-Spec) for antimony trisulfide.
“Antimony from the Stibnite Gold Project site served our national defense needs during World War II, and Perpetua is confident we can be part of the solution again,” said Perpetua ceo and president Laurel Sayer.
Antimony trisulfide is produced from high purity antimony ore feedstock and is used in small and medium calibre munitions, mortars, artillery, mines, flares, grenades, shoulder launched munitions and missiles. Production is dominated by China, which together with Russia and Tajikistan account for 90% of the world’s supply, with Vietnam and Myanmar being other major suppliers.
In the context of the US wishing to break its dependence, especially in the defence procurement context, on China and Russia, antimony has featured prominently in government debates. The urgency of the drive for domestic substitution has prompted the US government to even leverage the 1950 Defense Production Act to bolster investment in domestic critical minerals production.
The two grants of $100,000 each for two separate studies were awarded to Perpetua under the Defense Logistics Agency’s “Production of Energetic Materials and Associated Precursors” Small Business Innovation Research (SBIR) grant solicitation. The grant programme aims to reduce “foreign reliance and single points of failure for the domestic manufacturing of energetic materials” through the development of a domestic supply source.
Each study is expected to be completed within the next six to 12 months. The first will test existing samples of antimony trisulfide ore from the Stibnite project for development into antimony trisulfide to Mil-Spec. The second program will study alternative processing opportunities to develop Mil-Spec antimony trisulfide from high purity antimony metal. After the completion of the proposed programs under phase 1 finding, phase 2 funding could be made available for more advanced stage pilot-scale testing within the next year.
Historically, it was the gold rush of the 1890s that brought mining to the Thunder Mountain area, and Stibnite became a mining town in the early 20th century, with gold mining continuing at the site on and off until the 1990s. During WWII and the Korean War, the U.S. Government commissioned antimony and tungsten production from Stibnite for a limited period under the authority of the Strategic Metals Act of 1939.
